Open Radar

 
Summary:

When opening an app from a notification (and the app is already running in background), application:didReceiveRemoteNotification:userInfo:fetchCompletionHandler: will not be called.

Steps to Reproduce:
1. Add a `application:didReceiveRemoteNotification:userInfo:fetchCompletionHandler:` method to your UIAppDelegate
2. Open the app, then close it (let it run in background)
3. Have a push notification appear
4. Tap the notification to open the app with it

Expected Results:
- `application:didReceiveRemoteNotification:userInfo:fetchCompletionHandler:` will be called with the notification info.

Actual Results:
- Nothing happens

Regression:
- This is a regression from iOS 9
- `application:didReceiveRemoteNotification:userInfo:fetchCompletionHandler` is called just fine for background pushes, just not when app is opened from a notification
- UNUserNotification API for this seems to work

Notes:

Workaround is to *also* implement `application:didReceiveRemoteNotification:userInfo:` method. Then this one will be called when opening app from a notification, and the variant with the fetch completion handler will be called for background pushes.